Recently I’ve mentioned my morning smoothies. They’re a delicious way for me to increase my consumption of fruits and vegetables. Smoothies blend ingredients together, and every part of the ingredient remains in the drink, including the pulp. Now I am getting questions about a different, but related, topic: Juicing.

Juicing machines extract the liquid from fruits and vegetables. The pulp is typically discarded. The juicing trend had some early beginnings in the 1920s and 1930s, but it really took off in the 1970s. Since the 1990s, juicing has gone mainstream.

The upsides of juicing?

• The juice contains most of the vitamins and minerals found in the whole fruit or vegetable.

• It can be a delicious, healthy snack or even a meal replacement.

• It makes it easier to consume the daily recommendation of five servings of vegetables and three servings of fruit.

• Too often, when fruits and vegetables become very ripe, we toss them. Juicing is a great way to use them.

The downsides?

• What are the consequences of discarding that fiber-rich skin and pulp? Without the fiber, it is easier and quicker for our body to absorb the fructose (sugar). This can be disruptive to our blood sugar levels. Discarding the fiber means throwing away some of the vitamins and minerals. Fiber helps to normalize bowel movements, lowers the risk of colon cancer and hemorrhoids, lowers cholesterol levels, and helps to maintain a healthy weight.

• Juice that is heavy in fruit has a high calorie and sugar content. Snacking on an apple yields about 10 grams of natural sugar, but a glass of apple juice might contain three to six apples, and 30 grams of sugar or more.

• Juicing can be expensive, especially when organic produce is used. (Add to that the cost of a good machine.)

• Although juices have a lot of vitamins and minerals, they are carbohydrates, so most fruits and vegetables are low in healthy fats and protein. If you juice, I suggest that you include in your diet Greek yogurt, peanut butter, nuts and seeds, etc.

• If your juicing is in addition to meals, keep an eye on those added liquid calories.

For most of us, I like to recommend that instead of drinking a glass of apple juice, simply grab an apple. Still, drinking fresh juice is one good way to consume more vitamins and minerals. Do keep in mind that the ingredients make all the difference. To make your drink nutritious and far lower in sugar and calories, limit the fruit content: Instead of fruit, use mostly vegetables, like spinach and celery. Include great proteins like yogurt, peanut butter, non-fat milk or milk substitute. Enjoy!

Dr. Alan Frischer is former chief of staff and former chief of medicine at Downey Regional Medical Center.